A centrifugal compressor is a type of a turbo compressor. Such a centrifugal compressor is used at petrochemical plants, natural gas plants, and the like. The centrifugal compressor compresses natural gas and gas obtained by crude oil degradation. The centrifugal compressor sends this compressed gas to a pipeline and a reaction process of various plants. Such a centrifugal compressor includes a hub fixed to a main axis, and an impeller having a plurality of blades. Pressure energy and velocity energy are provided to gas by the centrifugal compressor rotating the impeller.
For example, Patent Document 1, listed below, discloses an impeller which has a plurality of main blades provided at equal intervals around a main axis. Seen from a planar view from a direction of the main axis, a leading edge of a main blade of the impeller is curved in a bow-shape in a direction opposite to a direction of rotation. Furthermore, a first angle formed by a line in a radial direction and a tangential line at a blade edge of the leading edge is greater than or equal to 10 degrees.
According to such a configuration, it is possible to prevent low-energy fluid from accumulating at a suction side of the main blade. By reducing an internal loss in this way, the compression efficiency increases.